Hi all, I bought an old beater a couple of months back (2004 Mazda3 2.0 Sedan) and I recently noticed that the coolant looks to be a bit low.
So I was wondering if it's OK to just top it up with some STP Universal Coolant? The coolant that's in my engine now is greenish and there is no FL22 sticker on the cap.
I've tried to read some other posts but considering i'm a complete car maintenance illiterate I didn't quite understand if I need to do a flush or if I can just top it up?
Thankful for any advice.